When human presence forces cheetahs to expend more energy, however, it put the animals’ survival at risk

Africa's lanky cheetahs are famous for being the world's fastest land animal, sprinting up to 75 miles per hour to chase down prey. But those swift cats, it turns out, spend surprisingly little of their time actually racing across the savannah or desert. Instead—just like their domestic counterparts—they spend the majority of their time sitting around, according to an article published today in Science.

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An international team of researchers traveled to the Kgalagadi Transfrontier Park and Karongwe Game Reserve in South Africa to observe 19 cheetahs in action. First, they captured the cheetahs, injected them with a harmless isotope solution and attached radio collars to the cheetahs. After letting the animals go, the researchers quietly stalked those cats for weeks at a time, meticulously tracking their movements and collecting urine samples, from which—thanks to the isotope solution—they could quantify daily energy expenditures.

The cheetahs, the researchers found, spent just 12 percent of their time actually moving. When they did hoist themselves up to go find food, the distance they covered positively corresponded to the size of prey they tracked down—the more they invested in travel, the bigger the reward.

About a quarter of the time, pesky hyenas or lions snagged the cheetah's hard-won meals. This wasn't a huge loss for the cheetahs, however. Even when their food was stolen, they required just over an hour's extra time to find a replacement snack, and that extra work only added about 12 percent more effort to their daily energy expenditures.

"What we found was that the cats' energy expenditure was not significantly different from other mammals of similar size – cheetahs may be Ferraris but most of the time they are driving slowly," biologist Mike Scantlebury, a co-author of the paper, said in a release. "If you can imagine walking up and down sand dunes in high temperatures day in, day out, with no water to drink you start to get a feel for how challenging these cats' daily lives are, and yet they remain remarkably adapted and resilient."

Cheetahs, in other words, are magnificently adapted to conserving their resources.

But if cheetahs are such perfectly efficient hunting machines, the researchers wondered, why have their populations declined from 100,000 to just 10,000 over the past century or so?

Humans, as usual, are most likely to be to blame. Depletion of cheetah prey species outside of reserves and infringement on their territory, the researchers think, forces the big cats to travel ever farther distances to find food. Those extra energetic demands likely have real-world costs for the cheetahs in terms of their ability to produce kittens and ensure that their young reach adulthood. Exerting that extra effort may even impact cheetahs' ability ot survive themselves. As Scantlebury explained,"Anything that we do to make them move farther to find prey – like depleting their prey stocks or erecting fences or barriers – makes life a lot harder for a cheetah."

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About Rachel Nuwer

Rachel Nuwer writes for Smart News and is a contributing writer in science for Smithsonian.com. She is a freelance science writer based in Brooklyn.

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